1. Field of the Invention
The present invention relates to an intracoelomic mobile body for introduction into a body cavity, and a capsule-type ultrasonic endoscope.
2. Description of the Related Art
In recent years, capsule-type medical apparatuses came into use as intracoelomic mobile bodies for introduction into body cavities.
Such capsule-type medical apparatuses do not require long and thin insertion portions typical for the endoscopes and are so formed as to be easily swallowed by a patient.
For example, a capsule-type ultrasonic endoscope described in Japanese Patent Application Laid-open No. H9-135832 has been proposed as such a conventional capsule-type medical apparatus.
In the capsule-type ultrasonic endoscope described in Japanese Patent Application Laid-open No. H9-135832, ultrasonic tomographic images (referred to hereinbelow as ultrasonic images) are obtained based on echo information obtained by transmitting ultrasonic pulses to a living body tissue and receiving them therefrom. Therefore, with the above-described conventional capsule-type ultrasonic endoscope, ultrasonic images could be acquired by passing the capsule-type ultrasonic endoscope through zones where a long thin insertion portion of the usual ultrasonic endoscope was difficult to insert.
In the conventional capsule-type ultrasonic endoscope, an ultrasonic transducer unit, which is a unit to be rotated, and a drive unit for rotating the ultrasonic transducer unit freely back and forth are enclosed in a capsule sheath serving as a casing. The configuration of the conventional capsule-type ultrasonic endoscope is such that the ultrasonic transducer unit transmits and receives ultrasonic pulses, for example, in the radial direction perpendicular to the longitudinal central axis of the capsule sheath, when the ultrasonic transducer unit is rotated by the drive unit.